Research Breakdown on L Carnitine Examine The Role of L Carnitine in Kidney Disease and Related Metabolic Dysfunctions L Carnitine Benefits for Male Erectile Dysfunction L Carnitine injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you L Carnitine and Male Fertility: Is Supplementation Beneficial?